Since the invention of the first galvanic cell by Alessandro Volta around in year 1800, various types of primary and secondary batteries, such as wet and dry batteries have been developed. A typical wet battery, for example, is Lead-acid battery. Lead-acid batteries include non-environmental friendly materials including sulphuric acid liquid electrolyte and lead electrodes. Non-rechargeable dry batteries include materials such as Zinc Carbon, Zinc Chloride, Mercuric oxide and Zinc, while rechargeable dry batteries include materials such as Nickel cadmium (NiCd), Nickel-metal hydride (NiMH) and Lithium ion (Li-ion).
In the case of dry batteries with non-replaceable electrolytes, they need to be disposed of after the useful life time of the battery has expired. While some wet batteries can have the electrolyte replenished, the process is generally hazardous and can lead to spilling of caustic materials.
Regardless, whether the battery is a wet battery or a dry battery, the disposal of the toxic material used in their fabrication pose a environment threat. This is especially true of the disposal of the heavy metals that often end up in the water system and affects both land organisms and aquatic organisms. Further, the bioaccumulation of these materials in the food chain results in negative long term effects on the ecological environment.
A conventional battery is not waterproof and cannot be directly used in water. For underwater applications, batteries typically must be encased in a waterproof housing structure or sealant to prevent water from diluting the electrolyte and the corroding electrodes.